// SPDX-License-Identifier: GPL-3.0-or-later
// Copyright (c) 2025 XujueKing <leadbrand@me.com>

// SuperVM 2.0 - Pedersen Commitment Implementation
// 架构师: KING XU (CHINA)
// Phase 2.2.3: Pedersen Commitments (Week 17-20)
//
// 实现 Pedersen Commitment 用于隐藏交易金额
// C = aG + bH, 其中 a 是金额, b 是致盲因子

use crate::privacy::types::*;
use anyhow::Result;

/// Pedersen Commitment Generator
/// 用于生成金额承诺
pub struct CommitmentGenerator {
    // TODO: Phase 2.2.3 - 添加椭圆曲线点操作
}

impl CommitmentGenerator {
    /// 创建新的生成器
    pub fn new() -> Self {
        todo!("Phase 2.2.3: Implement commitment generator")
    }
    
    /// 生成 Pedersen Commitment
    /// 
    /// # 参数
    /// - `amount`: 金额 (0 到 2^64-1)
    /// - `blinding_factor`: 致盲因子 (32 bytes random scalar)
    /// 
    /// # 返回
    /// Commitment C = amount*G + blinding*H
    pub fn commit(&self, _amount: u64, _blinding_factor: &[u8; 32]) -> Result<Commitment> {
        todo!("Phase 2.2.3: Implement Pedersen commitment")
    }
    
    /// 生成随机致盲因子
    pub fn generate_blinding_factor(&self) -> [u8; 32] {
        todo!("Phase 2.2.3: Implement blinding factor generation")
    }
}

/// Commitment Verifier
/// 用于验证承诺的有效性
pub struct CommitmentVerifier {
    // TODO: Phase 2.2.3 - 添加验证逻辑
}

impl CommitmentVerifier {
    /// 创建新的验证器
    pub fn new() -> Self {
        todo!("Phase 2.2.3: Implement commitment verifier")
    }
    
    /// 验证承诺和的平衡性
    /// 
    /// 验证: sum(inputs) = sum(outputs) + fee*G
    /// 
    /// # 参数
    /// - `input_commitments`: 输入承诺列表
    /// - `output_commitments`: 输出承诺列表
    /// - `fee`: 交易费 (明文)
    /// 
    /// # 返回
    /// 验证是否通过
    pub fn verify_sum(
        &self,
        _input_commitments: &[Commitment],
        _output_commitments: &[Commitment],
        _fee: u64,
    ) -> Result<bool> {
        todo!("Phase 2.2.3: Implement sum verification")
    }
}

/// 承诺加法 (同态加法)
/// C1 + C2 = (a1 + a2)G + (b1 + b2)H
pub fn add_commitments(_c1: &Commitment, _c2: &Commitment) -> Result<Commitment> {
    todo!("Phase 2.2.3: Implement commitment addition")
}

/// 承诺减法
/// C1 - C2 = (a1 - a2)G + (b1 - b2)H
pub fn sub_commitments(_c1: &Commitment, _c2: &Commitment) -> Result<Commitment> {
    todo!("Phase 2.2.3: Implement commitment subtraction")
}

#[cfg(test)]
mod tests {
    use super::*;
    
    #[test]
    #[should_panic(expected = "not yet implemented")]
    fn test_commitment_generator_placeholder() {
        let _generator = CommitmentGenerator::new();
    }
    
    #[test]
    #[should_panic(expected = "not yet implemented")]
    fn test_commitment_verifier_placeholder() {
        let _verifier = CommitmentVerifier::new();
    }
}
